1. Field of the Invention
The present invention relates to a UV-curable adhesive silicone composition, a UV-curable adhesive silicone composition sheet, an optical semiconductor apparatus, and a method for manufacturing the same.
2. Description of the Related Art
At the present time, since a silicone resin is excellent in the light resistance, it gathers an attention as a material for covering for sealing and protecting a light-emitting diode (LED) device (see Patent Literature 1). Further, in a field of light-emitting diodes, it is well known to use a phosphor as a wavelength converter (see Patent Literature 2). As a film in which a phosphor is dispersed, a thermosetting silicone resin is put into practical use (see Patent Literature 3). However, since a hydrosilylation reaction is used to cure, in many cases, a platinum-based catalyst is added in advance in a thermosetting silicone resin composition. As a result, from immediately after compounding, the reaction proceeds; accordingly, also a reaction control agent is added to secure the pot life. However, as a result thereof, a curing speed of the composition becomes slow and the composition flows during heat-curing to cause a problem of deformation of a shape thereof.
Further, in Patent Literature 4, a photocurable organopolysiloxane composition containing (methylcyclopentadienyl)trimethyl platinum as a curing catalyst is disclosed. The (methylcyclopentadienyl)trimethyl platinum is activated only when light is irradiated thereon; accordingly, under a non-irradiated state, the viscosity of the organopolysiloxane composition does not increase and the pot life is excellent. The Patent Literature 4 discloses a method where, upon irradiation of a light in an irradiation wavelength region of 200 nm to 400 nm, the (methylcyclopentadienyl)trimethyl platinum catalyst is activated to cure the organopolysiloxane composition.
However, according to a method of the Patent Literature 4, since a property before curing has fluidity, there is a problem that a resin composition flows before the organosiloxane composition is completely cured, and a cured material having a target shape can not be obtained.
Further, in some cases, it is necessary to cover only an optical semiconductor device (an LED chip, for example) or to form a bonding pad; accordingly, a film that can be patterned by lithography, which is not the conventional thermal curing type, is in demand. Still further, in LEDs, a resin layer that covers a LED chip is demanded to have also high thermal resistance and UV-ray resistance. Further, it is convenient when such a resin layer can be formed according to an existing manufacturing apparatus.
Further, generally in white LEDs, a method where by covering an LED chip with a silicone resin or an epoxy resin, in which a phosphor is dispersed, the phosphor is dispersed in the vicinity of the chip to convert a blue light into a pseudo-white light is adopted. However, when the phosphor is irregularly dispersed or unevenly concentrated, color deviation tends to occur. Accordingly, in order to obtain a uniform white light, it is necessary to uniformly disperse the phosphor in a covering resin layer. For this purpose, a method has been studied, in which, by applying a screen printing method or a sedimentation method, the phosphor is sedimented to disperse in the vicinity of a lower portion of the covering resin layer. However, there was a problem that a manufacturing step is made complicated and the degree of obtained stability is insufficient. Accordingly, an easy technology that allows to uniformly disperse a phosphor on a chip surface is in demand.